Plastic bottle preform and method for production thereof

Abstract

Provided is a PET bottle preform in which delamination is suppressed and a method for the production of the preform. An anchor layer containing a polyester-based urethane resin is formed on an outer surface of the preform.

The invention claimed is: 
     
       1. A preform for a plastic bottle comprising a mouth serving as an opening of the plastic bottle, a cylindrical body, and a bottom enclosing the cylindrical body,
 wherein the preform has a coating film in which an anchor layer containing a polyester-based urethane resin is formed on an outer surface of the preform, and 
 wherein a barrier layer containing polyvinyl alcohol and a leveling agent is formed on the anchor layer. 
 
     
     
       2. The preform according to  claim 1 , wherein a protective layer containing polyvinyl butyral (PVB) is formed on the barrier layer. 
     
     
       3. The preform according to  claim 1 , wherein the polyester-based urethane resin has a glass transition temperature (Tg) of approximately 65° C. to less than approximately 90° C. 
     
     
       4. The preform according to  claim 1 , wherein the polyester-based urethane resin has a glass transition temperature (Tg) of approximately 80° C. to approximately 85° C. 
     
     
       5. A plastic bottle comprising a mouth serving as an opening of the plastic bottle, a cylindrical body, and a bottom enclosing the cylindrical body,
 wherein the plastic bottle has a coating film in which an anchor layer containing a polyester-based urethane resin is formed on an outer surface of the preform, and 
 wherein a barrier layer containing polyvinyl alcohol and a leveling agent is formed on the anchor layer. 
 
     
     
       6. The plastic bottle according to  claim 5 , wherein a protective layer containing polyvinyl butyral (PVB) is formed on the barrier layer. 
     
     
       7. The plastic bottle according to  claim 5 , wherein the polyester-based urethane resin has a glass transition temperature (Tg) of approximately 65° C. to less than approximately 90° C. 
     
     
       8. The plastic bottle according to  claim 5 , wherein the polyester-based urethane resin has a glass transition temperature (Tg) of approximately 80° C. to approximately 85° C. 
     
     
       9. A method for the production of a preform for a plastic bottle, the method comprising the steps of:
 preparing a preform comprising a mouth serving as an opening of the plastic bottle, a cylindrical body, and a bottom enclosing the cylindrical body, and 
 coating an outer surface of the preform with an anchor coating agent containing a polyester-based urethane resin and drying to form an anchor layer, and 
 coating the anchor layer with a solution containing polyvinyl alcohol and a leveling agent and drying to form a barrier layer. 
 
     
     
       10. The method according to  claim 9 , further comprising the step of coating the barrier layer with a polyvinyl butyral (PVB) solution and drying to form a protective layer. 
     
     
       11. The method according to  claim 9 , wherein the polyester-based urethane resin has a glass transition temperature (Tg) of approximately 65° C. to less than approximately 90° C. 
     
     
       12. The method according to  claim 9 , wherein the polyester-based urethane resin has a glass transition temperature (Tg) of approximately 80° C. to approximately 85° C. 
     
     
       13. A method for the production of a plastic bottle, comprising a step of blow-molding a preform for a plastic bottle produced by the method according to  claim 9 .